This invention relates to safety devices and more particularly to adjustable buckle for safety belts, harness, etc.
Various types of safety devices, e.g., safety harnesses, parachute harnesses, safety belts, etc., make use of adjustable buckles to enable the harness, belt, etc. to be adjusted to a desired position, e.g., into close conformity with the person wearing the safety device. Some buckles make use of a chape or catch to extend through a selected one of plural openings or holes in the web or strap to be secured by the buckle. Such buckles, are not continuously adjustable since they can only be adjusted to the discrete positions established by the opening or holes in the web or strap. Continuously adjustable buckles are, however, available. Such buckles commonly make use of a rectangular rim or frame having a pair of side sections and a pair of end sections. A slidable arm is mounted between the side sections and is arranged to be slid therealong so that the arm can be disposed close to either of the end sections. Such buckles are normally fixedly secured to one portion of a web or strap by looping a portion of the web or strap about a first one of the end sections and then sewing or riveting the loop together. The free end of the web or strap to which the buckle is fixedly secured (or the free end of another web or strap) is arranged to be connected to the buckle by extending it through the frame's interior space between the other end section and the slidable bar, around the bar, and through the space between the bar and that end section, from which it exits the buckle. By pulling on the free end of the web the slidable bar with the web section therearound is drawn into close proximity with the other end section so that it is fractionally held in place.
While prior art adjustable buckles are suitable for enabling the continuous adjustment of a webs or straps connected thereby, they never the less leave something to be desired from the standpoint of their propensity to loosen, particularly if tension is not maintained on the web or strap. For example, in applications, where such buckles are used on safety harnesses worn by workers under conditions where no tension is maintained on the strap or web, if the worker bends over the buckle's slide may slip, thereby releasing the web. This accidental web releasing action is shown in FIG. 2.
Fortunately, the free end of the web or strap used in a safety device incorporating such an adjustable buckle is folded over itself at least twice and then sewn or otherwise fixed in place. This results in a thick free end of the web or strap, which is resistent to accidental escape from the space in the buckle's frame. Accordingly, while the buckle may loosen, it is unlikely to completely disconnect the web or strap sections it serves to connect. In some applications this may be, at worst, an inconvenience. However, in other applications, e.g., where the buckle is on a safety harness, the fact that the buckle can loosen may mean that a portion of the worker's body may slip out of the portion of the harness or safety belt with the loosened buckle. Obviously, such action may be intolerable.